Process for providing textile floor covering with latex resin foam coating



Jan. 3, 1967 U TE ET AL 3,296,009

PROCESS FOR PROVIDING TEXTILE FLOOR COVERING WITH LATEX RESIN FOAM COATING Filed Jan. 5, 1965 v c T /-END WALL 1 END WALL '9 IO fi I MOUNTING I: 3

I FLANGE i -l| ;T MOUNTING I I III-I I FLANGE INVENTOQS Tl-ggoooR SCHUTTE GUNTER JACOBS DE ZSOE STEINHERZ United States Patent 3,296,009 PROCESS FOR PROVIDING TEXTILE FLOOR COVERING WITH LATEX RESIN FOAM COATING Theodor Schiitte and Giinter Jacobs, Bremen, Germany, assignors to Hansawerke Lurman, Schutte & Co., Bremen-Hemelingen, Germany Filed Jan. 5, 1965, Ser. No. 423,431 3 Claims. (Cl. 117-10) Reference is made to our copending application Ser. No. 211,080 filed July 19, 1962, now abandoned, of which this is a continuation-,in-part.

Textile mate-rials, particularly rugs or carpets, are often provided on their bottom surface with a sizing. The latter consists in most cases of latex. In the manufacture of the so-called tufted carpets, in whichin contrast to woven carpets-the surface layer is not interlaced with the ground texture, such a coating layer on the rear-side is indispensable because only in this manner is it possible to firmly anchor or fasten the surface layer to the ground texture. In order to attain this, up to now a relatively thin and smooth layer of vulcanized latex was produced on the bottom surface of the carpet. Although this results ,in a satisfactory fastening of the surface layer in the ground texture, it does not render the carpet or rug sulficiently free from slip.

Attempts have been made to render rugs elastic and springy by placing them on a support of sponge rubber by firmly connecting by vulcanization or cementing such material supports with the rear surface of the rug. However, this two-step process is troublesome and expensive.

These difiiculties are avoided by the present invention in the manner described hereinafter.

According to this invention, rugs o-r carpets are provided in very simple manner with strongly adhering and durable foam layers, which render the rugs or the like free from slip, soft and elastic. In tufted carpets by the application of a single layer, i.e. without the use of a previously applied underlayer, excellent fastening of the surface layer in the ground texture is obtained simultaneously.

The process of the invention consists in that the foam mass applied is first subjected to a gelling procedure at increased temperature and then during passing between two pressure rollers, the upper of which is provided with a stamped or coin surface and is preferably cooled, while the lower has an elastic covering or coating, becomes firmly connected with the rug, is provided with a pattern and finally vulcanized and dried.

According to the invention, instead of a rug a widemeshed net-like fabric consisting of yarns, e.g. of jute or paper or the like, or another suitable carrier material, can be also used. In this manner, a layer to be applied can be prepared by itself in the form of a thick foil, which consists of vulcanized foam of the composition described hereinafter and which can "be applied as a cover or coating to any fabric.

The foam mass is applied to a net-like fabric preferably of jute or paper yarn and this net-like fabric is caused to pass on a support through the gelling zone until it arrives in front of the stamping roller. After gelling the net-like fabric provided with the foam coating can be introduced under the stamping roller, after which the foam and the net like fabric separate from the support and can be vulcanized in a manner known by itself in the vulcanization chamber. The finished net-like fabric having a foam coating is then rolled up.

It has been found that in using the process of the invention 150% and more fillers, based on the weight of latex-polyvinyl acetate dry substance, can be incorporated,

without the occurrence of too high sensitivity to mechanical abrasion.

Furthermore, a high content of filling materials results in a hardening and stiffening of the layer or coating. This is desirable in many cases, because tufted carpets, roughened fabrics, felts and the like are soft, flowing and somewhat flabby structures in uncoated condition, which need a certain strengthening in order to be suitable as floor covering.

According to the present invention, mixtures of natural latex with dispersions of polyvinyl acetate, are used.

It has been found that from foamed mixtures of latex with polyvinylacetate and suitable fillers, such as chalk, kaolin, barite, and the like, textile materials provided wit-h layers according to this invention can be prepared which possess any practically desired degree of stiffness and nevertheless exhibit satisfactory elasticity and freedom from slip.

The invention also relates to an apparatus for carrying out the present process. The essential parts of this apparatus are: a device for applying the foam mass; an oven for bringing about gelling; a pair of pressure rollers, the upper roller being provided with a stamping and capable of being cooled and a vulcanizing and drying oven.

In this apparatus preferably a supply device is used, which consist of a funnel, the walls of which are formed by moving bands and at the lower end of which strip off means are arranged.

The present process consists essentially of four operations or stages.

(1) Laying on of the previously prepared foam mass on the ground texture, and rendering the foam layer uniform;

(2) Causing the foam to gel or drying on;

(3) Stamping the foam by means of a pressure roller pair;

(4) Vulcanization and drying of the stamped foam.

The appended drawings illustrate a specific embodiment of and best mode for carrying out the invention, to which the invention is not limited.

In the appended drawings FIG. 1 is a diagrammatic illustration of an apparatus suitable for carrying out the process of the invention;

FIG. 2 illustrates a supply means used in the apparatus shown in FIG. 1, and FIG. 2a is a cross-section along line 2a in FIG. 2;

FIG. 3 is a cross-sectional diagrammatical illustration of a carpet prepared according to the invention, and FIG. 4 is a similar illustration.

The uniform application of the foam mass prepared in the manner described hereinafter, to the textile material to be coated, which is shown in FIG. 1 as a continuous band 1, must take placein view of the limited stability of such foamsin view of the advancing gelling of the foam, within a short period of time. If not a continuously operated foam-forming apparatus is used, which applies the foam to the fabric directly, according to the invention a device shown in FIG. 2 and 2a is used, which consists of conveyers 9 arranged in the form of a funnel opposite each other, with lateral termination, said conveyers being driven over guide rolls. The foam is filled into the funnel formed by the conveyers 9 and the bands are scraped off at the lower end by strip off means 10 so that no gelled or dried material can become clogged there. By this device even very difiicultly flowing foams can be processed and by adjusting the velocity of the bands any desired dosage of the foam to the goods treated can be obtained. The foam can be rendered uniform by means of a toothed iron plate (3). In an oven 4 gelling and drying on of the foam takes place at an increased temperature, preferably at about C. The material treated passes subsequent- 1y through a pair of pressure rollers (5 and 6), of which the upper roller 5 should be preferably provided with water cooling (not shown) and is stamped preferably with a wafer profile, while the lower roll 6 is smooth, serves merely for producing the counterpressure and has preferably an elastic covering.

Depending on the thickness of the carpet treated, the distance of the two rolls can be variably adjusted. The

stamped upper roller 5 presses the gelled or dried on foam to the ground texture in such manner that it enters an intimate connection with the latter and a honey-comb pattern is formed, the deepened parts of which firmly adhere to the ground texture, while the raised ribs provide for the desired elasticity and softness.

After this stamping, the material is after-treated in a vulcanizing or drying oven 7 in a manner known by itself, cooled in a cooling zone 8 and the finished carpet is rolled up.

In carrying out the invention, various patterns can be applied to the rear surface of the carpet or the like. The most varied effects can be obtained in dependence on the design of the stamping roller, on the process for preparing the foam and onthe amount of the masses applied. The stamping roller may be made in such manner that a trademark or the name of a firm appears on the rear side of the carpet.

However, in the case of tufted carpets, care should be taken that stamping should take place by corresponding design of the remaining fields of the stamping roller in such manner that a sufficient anchoring of the upper parts with the ground structure is safely brought about.

Example 1 In a suitable stirring machine 40 parts of centrifugelatex are mixed with some soap, the conventional vulcanizing and aging means, 36 parts of chalk and such an amount of water, that the mixture can be well stirred. The resulting latex is mixed with 15 parts of aqueous polyvinylacetate dispersion of 50% concentration and with parts of water, so that the resulting mass can be easily stirred. A homogeneous mixture is formed by stirring and this mixture is converted into foam by means of a beater-stirrer for foam-preparation in the proportion 1:4 with air and finally 10 parts of a 5% aqueous H NCl solution are stirred into the foam as gelling agent. The foam is applied in a layer of 6 mm. thickness to the textile material to be coated. Subsequently the foam thus applied is subjected to gelling at 120 C. for 23 minutes, stamped, and then vulcanized at 140 C. for 20 minutes. The result is a material provided with a stamped layer of 'foam rubber, which has a surprisingly satisfactory stability to abrasion of the sizing or dressing.

Example 2 50 parts of centrifuge-latex are mixed with some soap, with the conventional vulcanizing and aging means, 65 parts chalk, 60 parts polyvinylacetate dispersion of 50% concentration and such an amount of water that the mass can be easily stirred. This charge is converted into foam in the manner described in the above Example 1 and then applied to a textile material, caused to gel, and is stamped and vulcanized. The coating layer thus obtained is essentially stiffer than that formed in Example 1.

Example 3 The foamed material described in the above Example 1 or 2 is applied in the manner described in said examples to a wide-meshed net-like structure of jute, whereby a foam-foil is obtained which can be applied as a cover to the bottom surface of the textile material of a carpet.

In FIGURE 3, which illustrates Example 1 or 2, reference numeral 21 denotes the upper part of a textile carpet, 22 is a fabric of jute and 23 is a bottom layer prepared in the manner described in Examples 1 or 2. FIGURE 4 illustrates a foil comprised of a net-like jute fabric and the layer of foam material, as described in the above Example 3, reference symbol 24 denoting the jute fabric and 25 the foam material applied thereto.

It will be appreciated that this invention is not-limited to the details specifically described above and illustrated in the drawings and can be carried out with various modifications. Thus, in the above Example 1, to 40 parts of latex 4-6 parts of a 10% sodium oleate solution and in Example 2 to 34 parts of latex 3.5-5 parts of a 10% sodium oleate solution can be added. The foam formation can be carried out either discontinuously or by means of a well known continuously operating latex foam rubber machine which supplies the foam material from the machine through a tube directly to the surface to be coated with the foam material. The thickness of the finished foam material layer is in the range of about 1-5 mm. In carrying out the invention instead of centrifugelatex alone, a mixture of centrifuge-latex with e.g. equal parts of synthetic latex can be used. Gelling can be carried out preferably at about 120 C. in about 23 minutes and temperatures of l40120 C. gave satisfactory results in vulcanization and drying in a period of time of 15-25 minutes.

The parts recited are by weight if not otherwise stated.

It will be understood from the above that the process for providing according to the invention a textile floorcovering with a stiff resilient coating, consists essentially of the following steps. To one surface of the floor-covering a composition is applied, which consists of a foamed, uniform mixture of a rubber latex dispersion with an aqueous dispersion of polyvinyl acetate, said aqueous dispersion being compatible with said rubber latex, and with a filling material which is finely and uniformly distributed in said mixture and compatible with said mixture. parts by weight of said composition contains 8-90% preferably 25-65% of rubber and 38-0%, preferably 6-40% of polyvinyl acetate, all of these amounts being calculated on the total dry content of said composition. The ratio between the weight of dry rubber therein, to the weight of dry polyvinyl acetate being in the range between dry rubber to dry polyvinyl acetate of l to 3 up to 8 to l. The amount of the filling material in the composition being 0% to 200% by weight calculated on the total dry weight of rubber and polyvinyl acetate present in the composition. The composition applied in the above described manner to the floor-covering is heated to cause its gelling, and part of the gelled coating and the registering part of the textile floor-covering are strongly pressed together on of the entire coated surface of the floor-covering in order to attain strong adherence between said part of the coating and the corresponding part of the floor covering. A substantially weaker pressure is applied to the remaining part of the surfaces in order to form raised portions of high elasticity in the gelled coating. Finally, the coated floor-covering is vulcanized and dried by heating.

In converting the mixture of latex, polyvinyl acetate dispersion and filler into foam, air is introduced into the material to be foamed in conventional manner. For example, l-3 volumes air are used for 1 volume of said mixture, and the higher the amount of air used, the softer the vulcanized foam will be. As examples of vulcanizing agents which can be used in carrying out the invention, the following are mentioned:

2.5 parts by weight of sulfur,

0.5 parts by weight of 2-mercaptobenzothiazol, 0.75 parts by weight of zinc-N-diethyldithiocarbamate.

3.0 parts by weight of sulfur,

1.2 parts by weight of N-cyclohexylethyl-ammonium-cyclohexyl-ethyldithio-carbamate, and

0.8 parts by weight of zinc-N-ethylphenyldithiocarbamate- Gelation of the foamed material can be promoted by radiation with infrared rays in combination with a gelling agent, e.g. the agent described in the above Example 1. However, it will be understood that any other suitable vulcanizing agent and/or gelling agent can also be used. The water content of the coating material ready for aprange of 30-70%.

What we claim is:

1. Process for providing textile floor-coverings with a stiff resilient coating, essentially consisting of applying to one surface of the textile floor-covering a composition consisting essentially of a foamed substantially uniform mixture prepared by mixing (a) a rubber latex dispersion (b) with an aqueous dispersion of polyvinyl acetate and (c) with a filling material substantially finely and uniformly distributed in said mixture and compatible with said mixture, and by foaming the resulting mixture said aqueous dispersion of the polyvinyl acetate and said filling material being compatible with said mixture; 100 parts by weight of said composition containing 2.5 to 60 parts by weight of dry rubber and 1 to 60 parts by weight of dry polyvinyl acetate in a weight ratio of 1 to 3 up to 8 to 1 of rubber to polyvinyl acetate, to 200 parts by Weight of dry filler, all of said parts being based on the total Weight of dry rubber and dry polyvinyl acetate present in the composition; heating the resulting coated textile floor covering formed on one surface of the floorcovering, to gelling temperature in order to cause gelling of the coating; pressing together part of the gelled coating and the corresponding registering textile floor-covering adhered thereto on at least A to /3 of the entire coated surface of the floor-covering in order to attain strong adherence between said part of the coating and the corresponding part of the floor-covering, and applying substantially lower pressure than that applied in said pressing together of said part of the gelled coating and the textile plication in the manner described may be preferably in the floor-covering, to the remaining part of the coated textile floor covering in order to form raised portions of high elasticity in the gelled coating; drying and vulcanizing by heating the coated textile floor-covering.

2. Process as claimed in claim 1, in which 100 parts 10 by weight of the composition used contain -45% dry rubber, 640% dry polyvinyl acetate, and -75% of dry filler, said percent being based on the total weight of dry rubber and dry polyvinyl acetate.

3. Process as claimed in claim 1, in which the foam 15 is applied to the bottom surface of the textile material forming the floor-covering.

References Cited by the Examiner UNITED STATES PATENTS WILLIAM D. MARTIN, Primary Examiner.

T. G. DAVIS, Assistant Examiner. 

1. PROCESS FOR PROVIDING TEXTILE FLOOR-COVERINGS WITH A STIFF RESILIENT COATING, ESSENTIALLY CONSISTING OF APPLYING TO ONE SURFACE OF THE TEXTILE FLOOR-COVERING A COMPOSITION CONSISTING ESSENTIALLY OF A FOAMED SUBSTANTIALLY UNIFORM MIXTURE PREPARED BY MIXING (A) A RUBBER LATEX DISPERSION (B) WITH AN AQUEOUS DISPERSION OF POLYVINYL ACETATE AND (C) WITH A FILLING MATERIAL SUBSTANTILLY FINELY AND UNIFORMLY DISTRIBUTED IN SAID MIXTURE AND COMPATIBLE WITH SAID MIXTURE, AND BY FOAMING THE RESULTING MIXTURE SAID AQUEOUS DISPERSION OF THE POLYVINYL ACETATE AND SAID FILLING MATERIAL BEING COMPATIBLE WITH SAID MIXTURE; 100 PARTS BY WEIGHT OF SAID COMPOSITION CONTAINING 2.5 TO 60 PARTS BY WEIGHT OF DRY RUBBER AND 1 TO 60 PARTS BY WEIGHT OF DRY POLYVINYL ACETATE IN A WEIGHT RATIO OF 1 TO 3 UP TO 8 TO 1 OF RUBBER TO POLYVINYL ACETATE, 0 TO 200 PARTS BY WEIGHT OF DRY FILLER, ALL OF SAID PARTS BEING BASED ON THE TOTAL WEIGHT OF DRY RUBBER AND DRY POLYVINYL ACETATE PRESENT IN THE COMPOSITION; HEATING THE RESULTING COATED TEXTILE FLOOR COVERING FORMED ON ONE SURFACE OF THE FLOORCOVERING, TO GELLING TEMPERATURE IN ORDER TO CAUSE GELLING OF THE COATING; PRESSING TOGETHER PART OF THE GELLED COATING AND THE CORRESPONDING REGISTERING TEXTILE FLOOR-COVERING ADHERED THERETO ON AT LEAST 1/4 TO 2/3 OF THE ENTIRE COATED SURFACE OF THE FLOOR-COVERING IN ORDER TO ATTAIN STRONG ADHERENCE BETWEEN SAID PART OF THE COATING AND THE CORRESPONDING PART OF THE FLOOR-COVERING, AND APPLYING SUBSTANTIALLY LOWER PRESSURE THAN THAT APPLIED IN SAID PRESSURE TOGETHER OF SAID PART OF THE GELLED COATING AND THE TEXTILE FLOOR-COVERING, TO THE REMAINING PART OF THE COATED TEXTILE FLOOR COVERING IN ORDER TO FORM RAISED PORTIONS OF HIGH ELASTICITY IN THE GELLED COATING; DRYING AND VULCANIZING BY HEATING THE COATED TEXTILE FLOOR-COVERING. 